Device for adjusting and elastically locking moveable switch parts

ABSTRACT

A device for switching and elastically locking the end positions of movable switch parts, in particular switch tongues of grooved rail switches, including an axially displaceable rod ( 15 ) and a tube ( 17 ) surrounding the rod, in which a spring ( 29 ) encompassing the rod is braced against stops and locking members ( 26, 26 ′) capable of being displaced radially outwards are arranged, wherein the rod ( 15 ) has axially spaced-apart control stops ( 24, 25 ) for a radially inward position of the locking members ( 26, 26 ′) and the tube ( 17 ) has stops ( 32, 33 ) for the outward position of the locking members ( 26, 26 ′), wherein at least one ( 25 ) of the control stops ( 24, 25 ) of the rod ( 15 ) is displaceable relative to at least another one ( 24 ) of the control stops ( 24, 25 ) in the axial direction of the rod ( 15 ) and is capable of being fixed in the respective displaced position.

The invention relates to a device for switching and elastically lockingthe end positions of movable switch parts, in particular switch tonguesof grooved rail switches, including an axially displaceable rod and atube surrounding the rod, in which a spring encompassing the rod isbraced against stops and locking members capable of being displacedradially outwards are arranged, wherein the rod has axially spaced-apartcontrol stops for a radially inward position of the locking members andthe tube has stops for the outward position of the locking members.

In addition to using a so-called switch lock including a clamp-likecatch unit to lock movable switch parts, EP 603 156 A1 has alreadysuggested a configuration in which extra-axial loads on the lock areavoided, enabling the realization of a completely closed mode ofconstruction. In that known locking device, which may also be used as aswitching aid with the appropriate arrangement of pressure springs, arod is arranged in an axially displaceable tube, which, in turn, isitself arranged in a stationary tube. Locking members were displaceablyguided within the axially displaceable tube in the radial direction, andrecesses were each provided in the stationary tube and in the rod tocooperate with the locking members during displacement and in the endposition. When using such an arrangement as a switching aid in supportof the displacement movement, two pressure springs were used, whichinvolved high overall expenditures in terms of construction. Embodimentsof a switching aid are also known from AT 379 624, which uses a springrocker in which an angle lever is mounted in the crossing point of thearms, wherein a force accumulator is supported against the arms of thetwo angle levers by means of a pressure spring. Two spring rockers wereconnected with the two tongue rails via coupling rods.

From Austrian application A 2137/97 a switching aid used to elasticallylock movable switch parts is known, in which locking members are mountedin an axially spaced-apart relationship in cages arranged between a tubeand a rod, a pressure spring acting in the axial direction beingarranged between those cages. The rod is connected with the tongue railsvia coupling rods, wherein control grooves are provided about theperiphery of the rod to move the locking members into their differentpositions such that the pressure spring will be tensioned during theswitching procedure and exert an application force on the tongue in theposition of abutment of the tongue on the grooved rails. The ball cagesare axially movable to a limited extent such that they may be used withdifferent tongue impacts or different transverse movements of thetongue. The pressure spring in those known devices exerts differentforces on the tongue, depending on the tension length.

In EP-A1 603 156 different locking arrangements and switching aids aredescribed with an actuating means being arranged between twosubstantially identically constructed switching aids. In the main, suchconfigurations have relatively large structural lengths, thus renderingtheir use with small rail gages and, in particular, grooved rails notreadily feasible.

From FR-A-2 523 537 a switching aid comprising an integrated hydraulicactuating means has been known, wherein spring rockers are designed inthe form of two pressure springs which are supported on the housing ofthe ground box and enter into effect as predetermined dead centerpositions have been exceeded. Finally, EP-A1 0 779 197 discloses adevice for securing the end positions of hydraulic actuating drives.

All known devices have in common that their displacement strokes cannotbe readily changed and adapted to the respective requirements.

The invention aims to provide the conditions for a compactshort-structured actuating and switching aid which is suitable, inparticular, for use in grooved rails because of its short structurallength and which ensures that the resilient force of application on thetongue will become effective irrespective of a respectively adjustableactive displacement path in order to enable the creation of constantapplication forces on the tongue irrespective of the displacementstroke. Due to the compact mode of construction, also the possibleoccurrence of transverse forces is to be reduced so as to enable asubstantial reduction of wear.

To solve this object, the configuration according to the inventionessentially consists in that at least one of the control stops isfixable to the rod in a manner displaceable in the axial direction ofthe rod. Due to the fact that at least one of the control stops isfixable to the rod in a manner displaceable in the axial direction ofthe rod, it is feasible in a simple manner to adjust the stroke andhence the respectively required displacement path, the displaceabilityand fixability of the control stops, at the same time, ensuring that thefull and constant spring force becomes effective at the end of thestroke.

In this context, the configuration according to the invention in aparticularly simple manner may be devised such that the rod is dividedlydesigned, wherein the axial position of a rod part carrying a controlstop is variable relative to the other rod part. The change of the axiallength of the rod part with the simultaneous axial shift of the controlstop, in principle, may be realized in different ways. If the axiallength of one rod part is changed relative to the other rod part, thismay be effected, for instance, in that one rod part is designed to havean external thread and the second rod part is designed to have aninternal thread, the rod part having the external thread being screwedinto, or out of, the rod part having the internal thread. In aparticularly simple manner, the configuration may be devised such thatthe adjustable control stop is designed as an end face of a sleeve whichis capable of being screwed on the rod and connected on its free end tothe movable rail part via the coupling rod.

Such a sleeve carrying the adjustable control stop may be screwed on therod in a simple manner and is easily adjustable even subsequently. Aboveall, such a device also can be secured against unintentionaldisplacement, and arrested or blocked in the respectively selectedposition of the sleeve, in a particularly simple manner. To this end,the configuration preferably is devised such that the sleeve comprisesan internal thread into which a locking piece carrying an externalthread may be screwed in abutment on the rod in the manner of acounternut.

In order to comply with the requirements of a particularly compact modeof construction and hence ensure the preferred aptness for grooved railswitches, the configuration advantageously is devised such that theactuating means is comprised of a displaceable cylinder piston unitintegrated in the tube coaxially with the axis or rod, the maximumdisplacement path of which cylinder piston unit is larger than theadmissible adjustment range of the control stop or sleeve, respectively.Such an integration of a hydraulic actuating means in the switching andlocking device results in particularly short dimensions and, at the sametime, a reduced risk of eccentric off-center forces that might involvean increased wear. Particularly compact dimensions may be obtained ifthe piston of the cylinder piston unit is rigidly connected with therod, the piston rod being identical with the rod carrying the controlstops.

A configuration secured against the penetration of dust may be obtainedin that the tube is closed by end faces on both sides, wherein, in amanner known per se, the locking members preferably are designed asballs and radially guided in axially displaceable cages with the springbeing arranged between the mutually facing end faces of the cages.

In order to ensure the safe operation of the switching device even fromthe end positions, the configuration advantageously is devised such thatthe cages are located in end positions of the displacement path at adistance from the end faces of the tube.

In the following, the invention will be explained in more detail by wayof an exemplary embodiment schematically illustrated in the drawing.Therein, FIG. 1 is a top view on a schematic arrangement of the deviceaccording to the invention; and FIG. 2 is an axial section through adevice for elastically locking and adjusting switch parts, comprising anintegrated hydraulic actuating means.

FIG. 1 depicts a grooved rail switch, the movable switch tongues beingdenoted by 1 and the stock rail being denoted by 2. The switch tongues 1are connected with the device according to the invention for switchingand elastically locking movable switch parts 5 via a tongue rod assembly3 and universal joints 4. The switching device 5 is mounted in a firstU-shaped open box 7 together with the check rod assembly 6. Due to thecoupled mode of construction of the switching device, its installationin an open ground box is feasible, thus offering easy accessibility forservicing measures. The electrohydraulic drive 8 is firmly attached tothe box 7 in a tightly sealed separate box part 9. Both box parts areprovided with a cover plate, wherein the overall box structure isembedded so as to be insulated against the rails, if required. Ducts 10lead from the electrohydraulic drive 8 to a cylinder piston unitintegrated in the switching device 5 and described in more detail below,by which the tongue rod assembly 3 is actuated in the sense of doublearrow 11. Furthermore, it is apparent from FIG. 1 that the check rodassembly 6 arranged in parallel is provided with actuating plates 12which get into contact with inductive proximity switches 14 in therespective abutment position of the tongue, thus providing also anelectrical monitoring of the arrangement in addition to the mechanicalone. In order to adapt the proximity switches 14 to the required strokeof the switching device 5, the former are arranged in a manner thattheir mutual distance may be altered by the aid of an adjusting member13.

FIG. 2 depicts the switching device in a position in which the tongueabuts the stock rail on the left-hand side. The external tube, which isdenoted by 17, constitutes the housing for the switching device.Coaxially with the external tube are arranged a rod 15 and a sleeve 16screwed on the rod 15, which sleeve is connected with the universaljoints illustrated in FIG. 1 on its free ends. In the external tube 17are arranged two cylinder blocks 19 delimiting a cylinder space 20 andsealingly closing the latter towards outside and towards that part ofthe device which is illustrated in the drawing on the left-hand side. Acylinder piston 21 is screwed on the rod 15 in the region of thecylinder space 20 and may be powered with the pressure of a hydraulicliquid supplied and discharged via connections 18 provided in theexternal tube 17 and the hydraulic ducts 10 illustrated in FIG. 1. Inits left-hand section adjacent the cylinder piston unit, the externaltube 17 receives the device for elastically locking the switch tongue.The rod 15 on its circumference comprises a groove 22 having atrapezoidal cross section and includes a section 23 having a smallerdiameter, which section 23, together with the end face 25 of the sleeve16 screwed on the rod 15, forms a second groove that is also trapezoidalin cross section. The end face 25 of the sleeve 16, at the same time,constitutes a control stop for the radially inward position of a firstlocking member, which is comprised of balls 26 and radially guidedwithin an axially displaceable cage 27. The stop for the radially inwardposition of the second locking member, which is again comprised of balls26′ and a cage 27′, is realized by the stop 24 of the groove 22. Each ofthe cages 27 and 27′ comprises a supporting ring 28 and 28′,respectively, on which a pressure spring 29 acting between the cages 27and 27′ is supported. Tube sections 30 and 31 are inserted in thestationary external tube 17 and comprise stops 32 and 33 for theradially outward position of the locking members. The tube section 30 issupported on the cylinder block 19 and the tube section 31 is supportedon the external lid 34 which is fixed in its axial position by asecuring ring 35. During a switching movement in the sense of arrow 36,the spring 29 is at first compressed until the locking members 26 areshifted radially outwards into stop 33. The further displacement of therod 15 in the sense of arrow 36 is free of any spring force action untilthe locking members 26′ enter the groove 22 of the rod radially inwardsand cooperate with the stop 24 in a manner that any further displacementwill be assisted by a release of the pressure spring 29 and theresilient abutment of the right-hand tongue will be ensured under theaction of the pressure spring 29 after the right-hand end position hasbeen reached. After completion of the switching procedure, thehydraulics of the cylinder piston unit is switched to circulation, thusexerting no force on the actuating pistons 21. During a switchingmovement in the direction opposite to arrow 36, the pressure spring 29,which is supported on the stop 33 via the locking member 26, is againcompressed over a short path until the locking member 26′ emerges fromthe groove 22 to abut on stop 32. Since the pressure spring 29 is thensupported on the two stationary stops 32 and 33, any furtherdisplacement movement will be free of spring forces until the lockingmember 26 can enter the groove 23, whereupon the spring 29 will againexert a force on the control stop 25. As the left-hand end position isreached, the cage 27 has assumed a release position f relative to thelid 34 such that the retention force of the spring will only act on thesleeve 16. By screwing the sleeve 16 on and off, the axial position ofthe control stop 25 relative to the tube 15 is changed, thus enablingthe locking member 26 to enter the groove 23 at another point of timeduring a displacement movement opposite to the direction of arrow 36. Ifthe sleeve 16 is screwed in a manner that the length of the groove 23 isreduced, the stroke of the switching device will become larger, whereasit will get smaller by a rotation of the sleeve 16 in a manner that thelength of the groove 23 is increased. The respective stroke adjustmentis secured by the counternut 37. In this constructive configuration, thepressure spring 29 in its end position each has the same overall lengthL, thus exerting the same pressure force on the rod 15 and the end faceof the sleeve 16 in the respective end position. During the switchingprocedure, the spring 29 is additionally compressed by a slight extentand again released to its length L in the respective end position. Thus,a very short pressure spring may be chosen, since only a small springtravel is required during the switching procedure. There is, thus,provided a linear cylinder/spring rocker arrangement which may bereadily encapsulated and sealed towards outside because of its tubularmode of construction. The unit is adjustable for an adjustment stroke ofapproximately 35 to 60 mm, ensuring an end position securing force ofapproximately 2600 to 2800 N via the pressure spring. Due to the factthat the hydraulics of the cylinder piston unit is switched tocirculation in each of the end positions, the device also enables forcedswitching by the wheel flanges of the wheels (force opening of theswitch). The opening force of the switching mechanism amounts to about4000 N according to the maximum prestress of the end position securingmechanism and the displacement resistance of the pressure spring of thespring rocker mechanism. Overloads or damage to the adjustmentmechanism, however, will not occur in that case.

What is claimed is:
 1. A device for switching and elastically lockingthe end positions of movable switch parts, in particular switch tongues(1) of grooved rail switches, including an axially displaceable rod (15)and a tube (17) surrounding the rod, in which a spring (29) encompassingthe rod (15) is braced against stops (28, 28′) and locking members (26,26′) capable of being displaced radially outwards are arranged, whereinthe rod (15) has axially spaced-apart control stops (24, 25) for aradially inward position of the locking members (26, 26′) and the tube(17) has stops (32, 33) for the outward position of the locking members(26, 26′), wherein at least one (25) of the control stops (24, 25) ofthe rod (15) is displaceable relative to at least another one (24) ofthe control stops (24, 25) in the axial direction of the rod (15) and iscapable of being fixed in the respective displaced position.
 2. A deviceaccording to claim 1, wherein the rod (15) is dividedly designed, and anaxial position of a rod part carrying a control stop is variablerelative to another rod part.
 3. A device according to claim 1, whereinsaid at least one displaceable control stop is designed as an end face(25) of a sleeve (16) which is capable of being screwed onto the rod(15) and connected to the switch tongue (1) on its free end via acoupling rod (3).
 4. A device according to claim 3, wherein the sleeve(16) comprises an internal thread into which a locking piece (37)carrying an external thread may be screwed in abutment on the rod (15)in the manner of a counternut.
 5. A device according to claim 3, furthercomprising an actuating means comprised of a displaceable cylinderpiston unit integrated in the tube (17) coaxially with the rod (15),wherein a maximum displacement path of the cylinder piston unit islarger than an admissible adjustment range of the control stop or sleeve(16).
 6. A device according to claim 5, wherein the cylinder piston unitcomprises a piston rigidly connected with the rod (15).
 7. A deviceaccording to claim 1, wherein the tube (17) is closed by end faces (19,34) on both sides.
 8. A device according to claim 1, wherein the lockingmembers (26, 26′) are designed as balls and radially guided in axiallydisplaceable cages (27, 27′) with the spring (29) being arranged betweenmutually facing end faces of the cages (27, 27′).
 9. A device accordingto claim 8, wherein the cages (27, 27′) are located in end positions ofa displacement path of the rod (15) at a distance from end faces (19,34) of the tube (17).
 10. A device according to claim 2, wherein said atleast one displaceable control stop is designed as an end face (25) of asleeve (16) which is capable of being screwed onto the rod (15) andconnected to the switch tongue (1) on its free end via a coupling rod(3).
 11. A device according to claim 10, wherein the sleeve (16)comprises an internal thread into which a locking piece (37) carrying anexternal thread may be screwed in abutment on the rod (15) in the mannerof a counternut.
 12. A device according to claim 4, further comprisingan actuating means comprised of a displaceable cylinder piston unitintegrated in the tube (17) coaxially with the rod (15), wherein amaximum displacement path of the cylinder piston unit is larger than anadmissible adjustment range of the control stop or sleeve (16),respectively.
 13. A device according to claim 12, wherein the cylinderpiston unit comprises a piston rigidly connected with the rod (15). 14.A device according to claim 2, wherein the tube (17) is closed by endfaces (19, 34) on both sides.
 15. A device according to claim 2, whereinthe locking members (26, 26′) are designed as balls and radially guidedin axially displaceable cages (27, 27′) with the spring (29) beingarranged between mutually facing end faces of the cages (27, 27′).
 16. Adevice according to claim 15, wherein the cages (27, 27′) are located inend positions of a displacement path of the rod (15) at a distance fromend faces (19, 34) of the tube (17).
 17. A device according to claim 3,wherein the tube (17) is closed by end faces (19, 34) on both sides. 18.A device according to claim 4, wherein the tube (17) is closed by endfaces (19, 34) on both sides.
 19. A device according to claim 5, whereinthe tube (17) is closed by end faces (19, 34) on both sides.
 20. Adevice according to claim 6, wherein the tube (17) is closed by endfaces (19, 34) on both sides.
 21. A device according to claim 3, whereinthe locking members (26, 26′) are designed as balls and radially guidedin axially displaceable cages (27, 27′) with the spring (29) beingarranged between mutually facing end faces of the cages (27, 27′).
 22. Adevice according to claim 4, wherein the locking members (26, 26′) aredesigned as balls and radially guided in axially displaceable cages (27,27′) with the spring (29) being arranged between mutually facing endfaces of the cages (27, 27′).
 23. A device according to claim 5, whereinthe locking members (26, 26′) are designed as balls and radially guidedin axially displaceable cages (27, 27′) with the spring (29) beingarranged between mutually facing end faces of the cages (27, 27′).
 24. Adevice according to claim 6, wherein the locking members (26, 26′) aredesigned as balls and radially guided in axially displaceable cages (27,27′) with the spring (29) being arranged between mutually facing endfaces of the cages (27, 27′).
 25. A device according to claim 7, whereinthe locking members (26, 26′) are designed as balls and radially guidedin axially displaceable cages (27, 27′) with the spring (29) beingarranged between mutually facing end faces of the cages (27, 27′).
 26. Adevice according to claim 21, wherein the cages (27, 27′) are located inend positions of a displacement path of the rod (15) at a distance fromend faces (19, 34) of the tube (17).
 27. A device according to claim 22,wherein the cages (27, 27′) are located in end positions of adisplacement path of the rod (15) at a distance from end faces (19, 34)of the tube (17).
 28. A device according to claim 23, wherein the cages(27, 27′) are located in end positions of a displacement path of the rod(15) at a distance from end faces (19, 34) of the tube (17).
 29. Adevice according to claim 26, wherein the cages (27, 27′) are located inend positions of a displacement path of the rod (15) at a distance fromend faces (19, 34) of the tube (17).